Windows
Sash windows
- 6–8 weeks from survey to installation
- Own fitters — no subcontracting
- Prices updated 11 October 2026
Live price ranges
Sliding sash window
approx. 0.9 × 1.6 m
Value
REHAU uPVC
£1,300–£2,200
Contemporary
SMART or AluK aluminium · Alitherm Heritage
£1,700–£2,800
Engineered
Schüco aluminium
—
Signature slimline
Cortizo Cor Vision
—
A survey confirms the final figure.
Overview
Why sash windows?
Sliding sash windows define Georgian, Victorian and Edwardian homes. A good replacement keeps the proportions and the vertical sliding action while cutting draughts and noise.
We fit two systems: REHAU uPVC sliding sash (Value) and SMART Alitherm Heritage aluminium (Contemporary) for a slim, traditional sightline. Prices are for a typical 0.9 × 1.6 m window.
Period proportions
Vertical sliding sashes that keep the character of the house.
Warmer and quieter
Double-glazed sashes without the rattles and draughts of old timber.
No more painting
uPVC foils and powder-coated aluminium don't need repainting.
Heritage aluminium
SMART Alitherm Heritage for slim sightlines where uPVC isn't suitable.
Traditional details
Glazing bars and details chosen to match the originals.
Prices by brand tier
What sash windows cost
| Typical size, installed, each | ValueREHAU uPVC | ContemporarySMART or AluK aluminium | EngineeredSchüco aluminium | Signature slimlineCortizo Cor Vision |
|---|---|---|---|---|
| Sliding sash windowapprox. 0.9 × 1.6 m | £1,300–£2,200 | £1,700–£2,800Alitherm Heritage | Not offered in this tier | Not offered in this tier |
| See your own sizes and options | Price this in Value | Price this in Contemporary | Not offered | Not offered |
Contemporary
SMART or AluK aluminium
- Sliding sash windowAlitherm Heritage£1,700–£2,800
Not offered in Engineered or Signature slimline.
Indicative ranges for London and the South East, supplied and installed, including VAT. Updated 11 October 2026. A survey confirms your final price.
Tiers and brands
Which suits your home?
Styles and options
Made to your specification
Systems
- REHAU uPVC sliding sash
- SMART Alitherm Heritage aluminium
Finishes
- White and woodgrain foils (uPVC)
- Any RAL colour (aluminium)
Glass
- Double glazing
- Acoustic glass for busy roads
- Obscure glass
Good to know
Planning, regulations and timings
Conservation areas and listed buildings
If your home is listed, in a conservation area or covered by an Article 4 direction, changing the look of windows or doors may need planning permission or listed building consent. We flag this at survey and give you the product details your council will ask for.
Building Regulations and certification
Replacement windows and doors must meet Building Regulations for energy efficiency, safety glass, ventilation and fire escape. Each installation is certified through a competent person scheme such as FENSA, or signed off by building control, and the certificate is yours to keep for when you sell.
Survey to installation
Typically 6–8 weeks from survey to installation, agreed with you up front. One named project manager runs your job from survey to sign-off, and our own fitters do the work — we don't subcontract glazing.
Questions
Sash windows: your questions answered
How much do sash windows cost?
A typical sliding sash window (approx. 0.9 × 1.6 m) costs £1,300–£2,200 in Value (REHAU uPVC) and £1,700–£2,800 in Contemporary (SMART or AluK aluminium, Alitherm Heritage). Indicative, supplied and installed in London and the South East, including VAT; prices updated 11 October 2026. A survey confirms the final figure.
Can I replace timber sash windows in a conservation area?
Sometimes. Many councils expect replacements to match the originals closely and some require timber on listed buildings. An Article 4 direction can also remove permitted development rights. We flag this at survey so you can check with your council before ordering.
Are uPVC sash windows a good choice?
For most unlisted period homes they're the best-value way to keep the look while ending draughts and repainting. If you want slimmer frames, compare SMART Alitherm Heritage aluminium in the table above.
How long does it take to replace sash windows?
Survey to installation is typically 6–8 weeks from survey, agreed up front, with a named project manager and our own fitters.
Keep exploring
Related products and services
Aluminium windows and doors
Slim, strong aluminium from SMART, AluK, Schüco and Cortizo in any RAL colour.
uPVC windows and doors
A-rated REHAU uPVC — the best-value energy-efficient replacement windows.
Casement windows
The classic side- or top-hung window, in uPVC or slim aluminium.
Brands we install
REHAU, SMART, AluK, Schüco, Cortizo, VELUX, FAKRO and Cambridge Skylights — and the tier each sits in.
Begin your project
Get your price range in under two minutes
Choose your product and brand tier and see a live price range. No obligation, and a survey always confirms the final figure.